Aims: To study if minimally invasive strabismus surgery (MISS) is suitable for rectus muscle reoperations.
Methods: This study presents a series of consecutive patients operated on by the same surgeon at Kantonsspital St. Gallen, Switzerland with a novel MISS rectus muscle reoperation technique. Surgery is done by applying two small radial cuts along the muscle insertion. Through the tunnel obtained after muscle separation from surrounding tissue, a recession, advancement, or plication is performed.
Results: In 62 eyes of 51 patients (age 35.4±16.3 years) a total of 86 horizontal rectus muscles were reoperated. On the average, the patients had 2.1 strabismus surgeries previously. Preoperative logMAR visual acuity was 0.38±0.82 compared to 0.37±0.83 at 6 month (p>0.1). On the first postoperative day, in primary gaze position conjunctival and lid swelling and redness was hardly visible in 11 eyes, discrete in 15 eyes, moderate in 11 eyes, and severe in 15 eyes. One corneal dellen and one corneal erosion occurred, which both quickly resolved. The preoperative deviation at distance for esodeviations (n=15) of 12.5°±8.5° decreased to 2.6°±7.8° at 6 month (p<0.001). For near a decrease from 12.0°±10.1° to 2.9°±1.6° was observed (p<0.001). The preoperative deviation at distance for exodeviations (n=35) of -16.4°±8.5° decreased to -7.9°±6.5° at 6 month (p<0.005). For near a decrease from -16.5°±11.4° to -2.9°±1.5° was observed (p<0.005). Within the first 6 month, only one patient had a reoperation. At month 6, in 4 patients a reoperation was planned or suggested by us because of unsatisfactory alignment. No patient experienced persistent diplopia or necessitated a reoperation because of double vision. Stereovision improved at month 6 compared to preoperatively (p<0.01).
Conclusions: This study demonstrates that a small-cut, minimal dissection technique allows to perform rectus muscle reoperations. The MISS technique seems to reduce conjunctival and lid swelling in the direct postoperative period.